The main problem with getting file extensions is that they can be very confusing. There are a lot of different file types and file extensions, and it can be hard to know which one to use.
var fileName = "sample.txt"; var fileExtension = fileName.split('.').pop();
This code defines a variable called “fileName” and assigns it the value “sample.txt”. It then defines a variable called “fileExtension” and assigns it the value of the result of running the “split” method on the “fileName” variable, using a period (.) as the separator, and then running the “pop” method on that result. The net effect is that the “fileExtension” variable ends up containing the value “.txt”, which is the file extension of the “sample.txt” file.
Copy structures are a way of grouping related code together. They allow you to reuse code by copying it between different locations.
The most common use for copy structures is in object-oriented programming. In object-oriented programming, you often create objects and then use the same code to create instances of those objects. You can do this by creating a copy of the code that creates an instance of an object, and then changing the instance variable names to match the class name.